Interpretive Summary: In our vision of reducing insecticide usage on crops and promoting augmentative biological control of crop pests, we are exploring the potential of using native predators to suppress spider mite and aphid populations. Many spider mites and aphids are pests of plants in greenhouses, plantscapes and crop fields. We are currently studying ladybird beetles as predators of both pests and developing techniques to rear them more cost effectively. We designed experiments to determine if the pink-spotted ladybird beetle (Coleomegilla maculata) could develop and reproduce normally when feeding on unfamiliar, alternative food sources. We discovered that this ladybird beetle developed normally but laid more eggs when reared on Mediterranean flour moth eggs rather than brine shrimp eggs. Biochemical analysis revealed that Mediterranean flour moth eggs contained more soluble protein, which could explain, in part, why this food source was more suitable for C. maculata egg-laying. This new knowledge informs us that some alternative foods are more suitable (for ladybird beetles) than others and that biochemical analysis is often necessary to help explain the differences.

Technical Abstract:
We tested the hypothesis that Artemia franciscana Kellogg (brine shrimp, Anostraca: Artemiidae) eggs are suitable factitious, i.e., alternative, food to support the life history of a predatory ladybird beetle, Coleomegilla maculata DeGeer (Coleoptera: Coccinellidae). Using progeny from a stock colony reared solely on Ephestia kuehniella Zeller (Mediterranean flour moth, Lepidoptera: Pyralidae) eggs over multiple generations, we conducted feeding bioassays in replicated arenas (in three replicate trials) to determine the effects of A. franciscana on C. maculata growth, development and reproduction. In comparison to E. kuehniella eggs (control food), A. franciscana eggs were suitable for larval growth, development and survival, adult emergence and sex ratio of C. maculata. A. franciscana eggs were not suitable for reproduction; females oviposited less often when reared (since 1st instars) on a diet of A. franciscana eggs in comparison to the control food. The nitrogen content (a measure of crude protein) in A. franciscana did not differ significantly from that in the control food, but the C: N ratio of A. franciscana was lower than the control. Soluble protein in A. franciscana eggs was less than in the control food. In conclusion, A. franciscana eggs are suitable food for growth and development but not reproduction (egg production) in naïve C. maculata. Limited availability of soluble protein (i.e., preferred amino acids) in the A. franciscana diet could explain, in part, the low oviposition rate of C. maculata females in this study. Although not tested herein, lack of a generational history of exposure (i.e., naïveté) with A. franciscana probably had little or no influence on low egg production by C. maculata.